You installed a cookie banner, and suddenly your Google Ads Cost-Per-Acquisition (CPA) skyrocketed and conversion volume dropped by 40%. Is the banner broken? Probably not.
This is the "Unobserved Conversion" problem. When users deny cookies, the Google Ads pixel is blocked (in a standard setup). It cannot fire, so the conversion is never recorded.
The Wrong Fix
Do NOT set your Google Ads tags to "fire anyway" without consent checks. This is a direct violation of GDPR and can lead to account suspension or legal fines.
How to Recover Data Safely
Enable Consent Mode
Switch to "Advanced Consent Mode". This allows tags to load but strips them of cookie-setting powers when consent is denied.
Wait for Modeling
Google needs about 7 days of data to train its model. During this time, you will still see a gap.
Check "Conversions" Column
In Google Ads, look at the "Conversions" column. Modeled conversions are integrated directly here. Hover over the data to see if modeling is active.
For even better accuracy, combine Consent Mode with "Enhanced Conversions." This feature hashes first-party data (like email addresses) and sends it to Google to match with signed-in users, recovering conversions that cookies miss entirely.
Recovery Tools
Consent Mode
Recovers ~70% of ad-click-to-conversion journeys via modeling.
Enhanced Conversions
Recovers cross-device and view-through conversions.